QC procedures at Pol.Hi.Tech.

1. QC procedures at Pol.Hi.Tech. D.Bettoni, G.Cibinetto, S.Morganti, Luca Boni, Alfredo Pagano Ferrara Workshop May 26, 2003

2. Introduction • QC procedures at Pol.Hi.Tech. (PHT) have been discussed and (almost completely) defined in various meetings with the company. • Test equipment to be supplied partly by INFN, must be accepted by the company. • Acceptance criteria to be defined together with PHT.

3. Outline • General infrastructure • Barcode labelling • Inspection of profiles • Mechanical • Graphite coating • Resistivity Measurement • Inspection of jackets, endcaps, circuit cards • Gas tightness (leak test) • Wire check • Wire-cathode distance measurement • HV conditioning and plateau measurement • Long range tests

4. General Infrastructure • QC data and other relevant information collected by hand or, whenever possible, automatically with several DAQ stations. • Labview will be used to write the DAQ software and design the interface. • The DAQ stations will be operated by physicists on shift and/or PHT personnel. • All DAQ stations will be on a wireless LAN. • The DAQ station output will be simple text files. • Local production database will be available on site. • Data files will be transferred every day to an outside server to be imported in the official offsite LST database.

5. DAQ and Test Stations • Dedicated Stations • Resistivity measurement • Tube/Spool association • HV Conditioning and Plateau • Long term tests • 1-2 General purpose station(s) • Visual Graphite inspection • Gas tightness • Wire position • Capacitance

6. Local Production Database • Linux chosen as platform • Relational DB (my SQL, postGREP SQL ...) • Each Station will send files to a central server after each operation • Server will read files into the DB once a day • Raw data will be sent outside each day

7. Barcode labelling • The idea is to use barcode labels to identify the relevant parts that make up a tube as well as the tube itself. • Barcodes will also be used to enter the results of some QC tests, e.g. the defects found in the graphite coating. • Barcode labels will show also a number, to make it easier for the operator to look at.

8. Inspection of Profiles • Mechanical. All profiles checked by Minadek. Profiles checked on a sampling basis by PHT and measured in Padova. • Graphite coating. Visual check. Big defects get corrected. Small, acceptable defects recorded along with their positions. • Resistivity measurement. Resistivity on the bottom of the profiles will be measured automatically by means of a probe. Measurements will be taken at 50 cm intervals. Tubes accepted if resistivity within a predefined range. Acceptance criteria to be defined together with PHT.

9. Inspection of parts • Jackets. Check for mechanical integrity and that they have the correct dimensions. Done on a sampling basis after production. • Endcaps. Visual check of electrodes and gas inlets to make sure they are in good integrity. • Circuit cards. Visually check for cold solder joints and sharp wire ends. Circuit is then checked for proper continuity. Parts are cleaned by ultrasound at PHT.

10. Gas Tightness Gas leakage test is performed by completely submerging the tubes in water at 15-20 mbar overpressure. Less than 1 small bubble per minute is required. Leaking tubes are fixed with PVC glue if possible and tested again. If accepted, the information that the tube has been repaired will be registered and the position in which the repair has occured will be clearly marked. Tubes exceeding the 1 small bubble per minute limit will be rejected.

11. Wire check • Wire quality.A sample of wire at the beginning of each new spool will be sent to Princeton to be checked (mechanical, diameter, etc.). Track will be kept of which wires will be used in each tube. • Wire position. Possibility being considered to measure the wire position by means of a camera. • Wire connection and tension. Capacitance measurement at the end, to make sure everything is OK after all the handling etc.

12. HV conditioning, plateau, long range tests • Two test stations will be set up at PHT: one for HV conditioning and plateau measurement, one for long range tests. • These tests will be done with the ternary gas mixture: 88 % CO2, 9.5 % Isobuthane, 2.5 % Ar. • The long range tests will be carried out with the tubes in the box which will be used for shipping the tubes to the U.S. • Specifications for the plateau will be defined after plateaux are measured on prototypes in Ferrara and Princeton.

13. HV conditioning 7 day conditioning procedure: • 1 day to flow 6 gas volumes • 8 hours to 1 day to reach 2500 V. • 8 hours to 1 day to go from 2500 V to maximum voltage. Tubes drawing more than 5 A will be rejected • Keep 4 days at maximum voltage. The current drawn must not exceed 2 A for the first day and 100 nA for the remaining 3 days. Tubes failing these tests are rejected. Long range tests Each tube will be kept at the maximum operating voltage for a period of thirty days, during which the current drawn by the tube must not exceed 100 nA for more than 5 % of the time it is monitored. In addition no observed activity allowed in the second half of the history.

14. Summary • QC procedure at PHT well defined and agreed upon with the company. • Still a few questions to be addressed. • Need to purchase equipment to carry out tests at PHT. • Work is beginning to set up the general infrastructure and DAQ systems and to design the two test stations.